1. Field of the Invention
The present invention relates to safe nursing systems and methods for controlling safe nursing systems, and particularly relates to safe nursing systems and methods for controlling safe nursing systems that monitor the movement of a patient on a bed.
2. Description of the Related Art
In the past, an apparatus such as a biological information monitor has been used to measure vital signs such as blood pressure, body temperature, a cardiograph, arterial oxygen saturation, and breathing rate in order to monitor the biological state of a patient in a hospital, a household, or the like. When the measurement has returned an abnormal value, the apparatus or a remote central management apparatus to which the apparatus is connected visually and auditorily alerts a doctor or a nurse.
However, a situation such as where the patient has fallen out of his or her bed cannot be completely prevented simply by checking vital signs.
The following is an example of a sensor serving as a safe nursing system for preventing such falls from a bed. For example, an infrared sensor, an image sensor, or a beam sensor is an example of a sensor that does not come into contact with the patient. On the other hand, a floor-based foot sensor or a mat sensor placed under a sheet is an example of a sensor that comes into contact with the patient. A clip sensor is an example of a sensor affixed to the patient.
Such safe nursing systems can, within the sensing range of the sensors, mechanically convert the movement of the patient, such as whether or not the patient is on his or her bed, into simplified patterns and notify a caregiver (a nurse) thereof.
However, such safe nursing systems have had problems in that finer movements of the patient (coughing, rolling over, and so on) cannot be recognized, notifications are made without determining that the patient has moved, notifications are made after the patient has moved (for example, after the patient has fallen out of his or her bed), and so on.
In response to such problems, a rising monitoring method and apparatus has been proposed as a safe nursing system. This method and apparatus set a monitoring region for determining whether a subject (also called a “patient” hereinafter) has risen from his or her bed, use a camera to capture an image of a space from the side of the bed that includes the monitoring region, and determine that the subject is exhibiting rising behavior in the case where the size of a subject image region that fits within the monitoring region in the captured image has become greater than or equal to a predetermined value (see JP 2006-175082A).
However, with the method and apparatus according to JP 2006-175082A, the images are captured from the side, and there is a problem in that errors have increased due to nurses entering the captured image. Furthermore, depending on the installation location, the camera has also interfered with the nurses' work.
In addition, because the image is captured from the side, there is a problem in that it is difficult to detect the patient moving toward a side of the bed, which is an indication that the patient will fall out of the bed. Furthermore, there is a problem that in the case where the patient does not enter the monitoring region, such as in a case where the patient does not rise and instead rolls to the side and falls out of the bed, the patient's movement cannot be detected at all.
In addition, because rising behavior is determined based on the size of the patient's image region, there is a problem in that errors will occur in the determination results depending on the manner in which the patient rises (rising behavior and how far the patient's body enters the monitoring region), differences in body shape among patients, and so on.